SysMLv1: CAUTION: Only a Signal can be used for a SendSignalAction or MessageEvent trigger of an AcceptEventAction, not a Block or ValueType, even if they are valid types for a SysML FlowProperty! But you can "wrap" a Block or ValueType in a Signal.
A SignalEvent represents the receipt of an asynchronous Signal instance. Source Unified Modeling Language 2.5.1
A CallEvent models the receipt by an object of a message invoking a call of an Operation. Source Unified Modeling Language 2.5.1
A trigger for an AnyReceiveEvent is triggered by the receipt of any message that is not explicitly handled by any related trigger. Source Unified Modeling Language 2.5.1
An Event is the specification of some occurrence that may potentially trigger effects by an object. Source Unified Modeling Language 2.5.1
A MessageEvent specifies the receipt by an object of either an Operation call or a Signal instance. Source Unified Modeling Language 2.5.1
trigger_with_ports: If a Trigger specifies one or more ports, the event of the Trigger must be a MessageEvent. Source Unified Modeling Language 2.5.1
